Railway signaling



Oct. 12, 1937. G. R. PFLASTERER 2,095,675

RAILWAYv S IGNALING Filed Aug. 14, 1956 4 2 Sheets-Sheet 1 x Q a g a 9 E Q? EV E I N N N Q."

INV TOR A GQOP QR. f JZLPPQR" & BY

H15 ATTORNEY Oct. 12, 1937. G. R. PFLASTERER RAILWAY SIGNALING Filed Aug. 14, 1936 2 Sheets-Sheet 2 QNN MN mE l VE TOR George HJ fiZZFLQPQP. BY

Hi5 ATTORNEY Patented Oct. 12, 1937 were 2,095,675 RAILWAY srGNALrNG George R. Pfiasterer, Swissvale, Pa, assignor to The Union Switch & Signal Company, Swissvale, Pa, a corpcration of Pennsylvania Application August 14,

16 Claims.

My invention relates to railway signaling systems wherein the signals normally indicate stop and are changed to indicate proceed or caution only when a train is approaching.

Specifically, my invention relates to apparatus, in a system of the type described, for automatically clearing the signals upon the approach of a train which apparatus does not require any additional line conductors pver and above those usually provided for the signal control circuits.

I will describe two forms of apparatus embodying my invention, and will then point out the novel features thereof in claims.

Figs. 1A and 1B of the accompanying drawings are diagrammatic views, which when placed end to end in the order named, illustrate one form of apparatus embodying my invention. Fig. 2 is a diagrammatic view illustrating a modification of a portion of the apparatus shown in Fig. 1B and also embodying my invention.

Similar reference characters refer to similar parts in each of the several views.

Referring first to Figs. 1A and 1B, the reference characters 6 and designate the rails of a stretch of track over which traffic normally moves in the direction indicated by the arrows. The rails 6 and l are divided by insulated joints 8 into track sections W-X and X-Y. Each track section is divided into at least two sub-sections IT, 2T, 3T, 4T, etc. Each sub-section is provided with a track battery 9 connected across the rails at one end of the sub-section and with a track relay, designated by the reference character TR with a prefix the same as the numerical prefix of the associated sub-section, connected across the rails at the other end of the sub-section.

Each section is provided with a signal designated by a suitable distinguishing reference character. Each signal, as here shown, comprises a proceed lamp G capable of displaying a green light, a caution lamp Y capable of displaying a yellow light, and a stop lamp R capable of displaying a red light.

For controlling the signals, each section is provided with a polarized direct current relay designated by the reference character HD with a prefix the same as the reference character of the associated signal. For governing the polarized relays, each section is provided with a pair of line conductors each extending to the signal in advance and each including a front contact of each of the associated track relays. As will be explained more in detail hereinafter, the line conductors of each section are at times supplied with 1936, Serial No. 95,998

alternating current as well as with direct current. The impedance of the polarized relays HD is of such value as will prevent the flow of alternating current in these relays.

Each section is provided with a source of direct current, here shown as a battery IS with its terminals designated by the reference characters B and C.

The polarity of the current supplied to the line conductors for the section in the rear is governed by the relay I-ID associated with the section in advance. That is, the line conductors for the section next in rear are supplied with direct current of normal polarity or reverse polarity according as the relay HD associated with the section in advance is energized or deenergized, respectively.

For supplying alternating current to the associated line conductors, each section is provided. with a transformer, designated by the reference character N with a prefix the same as the reference character of the associated signal, and having a primary winding l5 and a secondary winding It. Each secondary winding I6 is connected across the associated line conductors by a condenser designated by the reference character P with a prefix the same as the reference character of the associated signal.

For supplying alternating current to the primary winding it of the transformers N, each section is provided with a device designated by the reference character A with a prefix the same as the reference character of the associated signal.

As here shown, each device A is an alternator of the vibrating reed type. Referring to alternator 1A, for example, an elastic member I!- is caused to vibrate between terminals I8 and I9 by a control Winding 20. In the deenergized condition of alternator A, member I? does not connect with either terminal H3 or H] but does connect with a terminal 2|. When energy is supplied to the alternator, winding 20 will attract member causing it to connect with terminal l9 and to move away from terminal 2|, causing winding 2|! to become deenergized. Upon the deenergization of winding 23, the resilience of member will cause it to move away from terminal l9 and to connect with terminal 58 as well as with terminal 2|. The circuit for winding 20 being then again completed through terminal 2|, winding 20 will again attract member ll causing the cycle of operation just described to be repeated. Winding 20 therefore will be repeatedly energized and deenergized as l ng as energy is supplied to its control circuit.

' reverse direction. Alternating current therefore will be induced in. secondary winding E6 of transformer IBN as long as alternator IBA is operating.

For controlling. the alternators A, as well as for controlling the lamp circuits of the associated "signal and for connecting the associated relay HD to the corresponding line conductors, each section is provided with an approach relay designated by the reference character AR with a prefix the same as the reference character of the nal.

;in the usual manner.

'is deenergized .(see signal l2), a readily traced circuit for the stQp lamp R of that signal is stop.

associated signal. As here shown, each relay AR is normally deenergized and is connected in series with the line circuit for the section'next in rear. The pickup value of each relay AR is such that these'relays will not become picked up on the value of the current required by the relay HD for the section'next in rear but will only become picked up if a path'of comparatively low resistance is closed. For example, relay l-IAR Will not become picked up bythe current supplied to relay iilHD from battery I3 at signal H; but will only become picked up if either track relay 2TB. or 3TB, is released so that either the path including shunt 22 or the path including shunt 23 is closed. In other words, the relays AR will become picked up only when the section next in rear is occupied by a train. Connected across the winding of each relay AB is a resistor 24 which is provided to bypass the alternating current supplied to the line circuit controlling such relay so that the relays AR will not become picked up by alternating current.

.Also for connecting the relays HD to the associated line conductors, each section is provided with an auxiliary approach relay designated by the reference'character AX with a prefix the same as the reference character'of the associated signal. Each relay AX receives energy from the line conductors for the section next in rear through an asymmetric unit and a transformer designated by the reference characters Q and M, respectively, each with a prefix the same as the reference character of the associated sig- It will be readily apparentthat the relays AX can be energized only when the line con- .ductors' for the section next in rear are supplied with alternating current.

The polarized relays I-ID control the signals That is, when relay I-ID established so that, when relay lZAR becomes energized, the signal will display a red light to indicate stop. When relay HD is energized in the reverse direction (see signal l I), a readily traced circuit for the caution lamp Y is established so that, when relay MAR becomes energized, that signal will display a yellow light to indicate approach next signal prepared to When relay HD is energized in the normal direction (see signal it), an easily traced circuit for the proceed lamp G is established so .that, when relay WAR becomes energized, that signal will display a' green light to indicate proceed at normal speed.

the left of location W so that track relay iTR is deenergized to cause the pickup of relay IOAR. The circuit for relay WAR may be traced from terminal B of battery l3 at signal I 0 through resistor 24 and relay WAR in multiple, back point of contact 26 of relay IUHD, back point of contact 2'! of relay ITR, shunt 28, back point of contact 29 of relay ITR, primary winding 30 of transformer WM, and back point of contact 3| of relay lflI-ID to terminal C of battery I3.

Since relay WAR is energized, relay lllHD is connected to the line conductors for section WX by front contact 32 of relay MAR, and a circuit is closed to cause the operation of alternator NBA over front contact 33 of relay WAR.

Since secondary winding it of transformer MN is energized by alternating current, the line circuit for section WX is supplied with alternating current so that primary winding 34 of transformer MM is energized. The energization of primary winding 35 induces current in secondary winding 35 so that relay H AX is energized through asymmetric unit HQ. The circuit for primary winding 34 of transformer HM may be traced from one terminal of secondary winding iii of transformer iiiN, through condenser I DP, front point of contact 36 of relay ZTR, front point of contact 3? of relay STR, primary Winding 34 of transformer HM, front point of contact 39 of. relay HHD, resistor 2 3, battery I3 at signal H, front point of contact 38 of relay HHD, front contact 48 of relay STR, front contact il of relay ZTR to the other terminal of transformer ltN.

Since relay HAX is energized, its front contact 42 is closed to connect relay HHD with the line conductors for section XY so that relay l lHD is energized in the reverse direction. The circuit for relay ill-ID may be traced from terminal B'of battery it at signal #2 through resistor 2 and relay lZAR in multiple, back point of contact 33 of relay IZHD, front point of contact 44 of relay 5TB, front point of contact 45 of relay GTR, relay HHD, front point of contact 32 of relay iiAX, front point of contact 46 of relay 4TB, front point of contact 47 of relay STR, primary winding 34 of transformer IZM, and back point of contact 48 of relay i2I-ID to terminal C of battery l3 at signal l2.

Since relay HHD is energized, relay IEIHD is energized in the normal direction so that signal I0 is caused to display the normal proceed indication. The circuit for relay lllI-ID may be traced from terminal B of battery l3 at signal l! through resistor 24 and relay MAR in multiple, front point of contact 39 of relay HHD, primary winding 36 of transformer IIM, front point of contact 3 of relay 3TB, front point of contact 36 of relay Z'I'R, front contact 32 of relay WAR, relay ESHD, front point of contact t! of relay ZTR, front point of contact 49 of relay 3TB, and front point of contact 38 of relay HHD to terminal C of battery It at signal l l.

The polarized relays HD are preferably of the retained neutral type so that a momentary energization of the red lamp will be avoided during periods of change of polarity. For example, when front contact 32 of relay I EAR becomes closed, relay HIHD will be momentarily energized in the reverse direction until such time as the relay HHD becomes energized. If the retained neutral feature, however, is provided, the back neutral contacts of relay IGHD will not become momentarily closed to cause a flash of the red lamp when the energization of the relay IOHD is changed from the reverse direction to the normal direction by the picking up of relay ill-ID.

The relays AR are provided with a slow releasing characteristic so thatthe circuit for the associated relay HD will not become opened when the neutralcontacts of such associated relay HD are changed from areleased to a picked up condition. For example, when relay IOHD becomes energized, the circuit for relay ifiAR will be momentarily opened during the time contacts 26 and 31 of relay IElI-ID are moving between their. backpoints and their'front points. Due to the slow releasing characteristic, however, relay IBAR will remain in its picked up condition during this period so that the energization of relayiiiHD will not be disturbed. The relays AX are proxided with a slow releasing characteristic so that the line circuit for the control of the associated relay I-ID will remain closed during the periods when the latter relay is being trans ferred to control by the associated relay AR. For example, when the train K enters section WX, relay ZTR. will become released so that energy will be disconnected from relay l IAX and so that the relay llARwill become picked up.

, The slow releasing feature of relay HAX insures that the line circuit for the control of relay HHD will remain closed until such time as relay HAR becomes picked up. Relay III-ID, there,-

fore, remains in its energized condition.

Referring now to Fig. 2, I have shown herein one signal and associated apparatus which, when included in a system with wires 59 and 5! at the right connected to wires 52 and 53, respectively, at the left, will provide two-block, threeindication, signaling similar to that described for the apparatus shown in Figs. 1A and 1B.

The principal difference between the system illustrated in Fig. 2 and that illustrated in Figs. 1A and 1B is that the relay AR inFig. 2 is normally energized instead of normally deenergized. In order-to provide a closed circuit for the normal energization of the relay AR, a resistor J has been substituted for the condenser P between the secondary winding l6 of the transformer N and the associated line circuit.

When the rear section becomes occupied by a train, the releasing of the track relay opens the circuit for the relay AR, so that its back contacts 54 and 55 become closed. The closing of back contact 54 connects relay HD to itsline circuit and the closing of back contact 55 initiates the operation of alternator A and energizes one of the signal lamp circuits depending upon the condition of relay HD.

Otherwise the apparatus operates in a manner similar to that described for the apparatus shown in Figs. 1A and 1B and it is considered, therefore,

unnecessary to provide further detailed explanation of the operation of the apparatus shown in Fig. 2.

. no train is approaching, only a relatively small amount of energy is required.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that Various changes and modifications may be made therein within the scope of the appended claims without depart ing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a forward and a rear section as Well as an intermediate section of railway track, an approach relay normally in one condition but operable to a different condition when the rear section becomes occupied by a train, an auxiliary relay normally in one condition but operable to a different condition when said approach relay is in its different condition, a signal control relay for the forward section and a signal control relay for the intermediate section, a circuit for supplying energy to the signal control relay for the forward section including a contact which is closed when said auxiliary relay is in its different condition, and a circuit for supplying energy to the signal control relay for the intermediate section governed by the signal control relay for the forward section and including a contact which is closed when said approach relay is in its different condition.

2. In combination, a forward and a rear section as Well as an intermediate section of railway track, an approach relay normally in one condition but operable to a different condition when the rear section becomes occupied by a train, an auxiliary relay normally in one condition but operable to a different condition when said approach relay is in its different condition, a first signal control relay for the forward section and a second signal control relay for the intermediate section, means for energizing said first signal control relay when said auxiliary relay is in its different condition provided the forward section is then unoccupied, and means for reversibly energizing said second signal control relay in accordance with the condition of said first relay when said approach relay is in its different condition provided the intermediate section is then unoccupied.

3. In combination, a forward and a rear section as well as an intermediate section of railway track, an approach relay normally in one condition but operable to a different condition when the rear section becomes occupied by a train, an auxiliary relay normally in one condition but operable to a different condition when said approach relay is in its different condition, a pole changer for the forward section governed by traffic conditions in that section and by said auxiliary relay, and traffic governing means for the intermediate section governed by said pole changer and by said approach relay.

4. In combination, a forward and a rear section as well as an intermediate section of railway track, an approach relay normally in one condition but operable to a different condition when the rear section becomes occupied by a train, an auxiliary relay normally in one condition but operable to a different condition when said approach relay is in its different condition, a pole changer for the forward section governed ,by traffic conditions in that section and by said auxiliary relay, a signal control relay governed by said pole changer and by said approach relay,

and a signal for the intermediate section governed by said signal control relay.

5. In combination, a forward and a rear section as well as an intermediate section of railway track, an approach relay normally in one condition but operable to a different condition when the rear section ibecomes occupied by a train, an auxiliary relay normally in one condition but "operable to a different condition when said approach relay is in its different condition, a first relay for the forward section and a second relay for the intermediate section, a first circuit for said first relay and a second circuit for said sec ond relay, meansfor closing said first circuit "when said auxiliary relay is in its different condition provided said forward section is then unoccupied, rneans for supplying said second circuit with current. in one direction or another according as said first relay is energizedor deenergized, respectively, and ,means for closing said second circuit when said approach relay is in its different condition provided the intermediate section is then unoccupied.

6.'In combination, a forward and a rear as well as an intermediate section of railway track, a normally deenergized approach relay which becomes energized when the rear section is occupied by a train, a normally deenergized auxiliary relay which becomes energized when said approach relay is energized, a first relay for the forward section and a second relay for the intermediate section, a circuit for supplying energy to said first relay including afront contact of said auxiliary relay, and a circuit for supplying energy to said second relay governed by said first relay and including a front contact of said approach relay.

7 '7. In combination, a forward and a rear as well as an intermediate section of railway track, a

normally energized approach relay which becomes deenergized when the rear section is cocupied by a train, a normally deenergized auxiliary relay which becomes energized when said approach relay is deenergized, a first relay for v the forward section and a second relay for the intermediate section, a circuit for supplying energy to said first relay including a front contact 7 of 'said auxiliary relay, and a circuit for supplying energy to said second relay governed by said first relay and including a back contact of said approach relay.

8 Incombination, a forward and a rear as well as an intermediate section ofrailway track eachv provided with a track circuit including a track relay; a normally denergized approach relay, means including a back contact of the track relay for the rear section for energizing'said approach relay, a normally deenergized auxiliary relay, means including a front contact of said approach relay for energizing said auxiliary re- .an approach relay normally in one condition but Ioperable to a different condition when said rear section becomes occupied, a signal control relay, a circuit for said signal control relay governed by-tramc conditions in the intermediate section and including a pair of conductors as well as a contact which is closed when said approach relay is in its different condition, a. normally deenergized auxiliary relay, means including said pair of conductors for energizing said auxiliary relay when said approach relay is in its difierent condition, a pole changing relay for governing the direction of energization of said pair of conductors, and means for governing said pole changing relay in accordance with traffic conditions in the forward section effective when said auxiliary relay is energized.

10. In combination, a forward and a rear as well as an intermediate section of railway track, an approach relay normally in one condition but operable to a different condition when said rear 2 section becomes occupied, a signal control relay for the intermediate section and responsive only to current of a particular character, a pair of line conductors extending through the intermediate section and connected to said signal control relay when said approach relay is in its different condition, means including a pole changer for the forward section for supplyingsaid pair of conductors with current of said particular changer under control by traffic conditions in the forward section.

11. In combination, a forward and a rear section as well as an intermediate section of railway track, a pair of conductors for the intermediate section, a direct current signal control relay for the intermediate section, an approach relay normally in one condition but operable to a different condition when'the rear section becomes occupied by a train, means efiective to connect said signal control relay to said pair of conductors and also to supply said pair of conductors with alternating current when said approach relay is in its different condition, a direct current auxiliary relay receiving energy from said pair of conductors through an asymmetric unit, and means effective when said auxiliary relay is energized to supply said pair of conductors with direct current of one polarity or the other according to trafiic conditions in the forward section.

12. In combination, a forward and a rear secrelay is in its different condition, a direct current auxiliary relay receiving energy from said pair of conductors through an asymmetric unit, and means effective when said auxiliary relay is energized to supply said pair of conductors with direct current in one direction or the other according to traffic'conditions in the forward section.

13. In combination, a forward and a rear section as well as an intermediate section of railway track, a pair of conductors for the intermediate section, a direct current signal control relay for the intermediate section; an approach relay normally in one condition but operable to a different condition when the rear section becomes occupied by a train, means effective to connect said signal control relay to said pair of conductors when said approach relay is in its difierent condition, an alternator capable of supplying alternating current to said pair of conductors, means effective to cause the operation of said alternator when said approach relay is in its different condition, a pole changer connected between a source of direct current and said pair of conductors, and means responsive only to alternating current effective when energized to place said pole changer undercontrol by traffic conditions in the forward section.

14. In combination, a forward and a rear section as well as an intermediate section of railway track, a pair of conductors for the intermediate section, a direct current signal control relay for the intermediate section, an approach relay normally in one condition but operable to a different condition when the rear section be- .comes occupied by a train, means effective to connect said signal control relay to said pair of conductors when said approach relay is in its different condition, an alternator capable of supplying alternating current to said pair of conductors, a circuit for energizing said alternator including a contact which is closed when said approach relay is in its different condition, a pole changer connected between a source of direct current and said pair of conductors, and means responsive only to alternating current efiective when energized to place said pole changer under control by traflic conditions in the forward section.

15. In combination, a stretch of railway track divided into sections, a signal for each section, a signal control circuit for each section for supplying energy to the associated signal, an approach relay for each section normally in one condition but operable to a different condition when the section next in rear of the associated section becomes occupied by a train, means for each section effective to connect its signal with the corresponding control circuit when the associated approach relay is in its different condition, an auxiliary relay for each section normally in one condition but operable to a different condition when the approach relay for the section next in rear is in its different condition, and means for each section effective toconnect its signal with the corresponding control circuit when the associated auxiliary relay is in its different condition.

16. In combination, a stretch of railway track divided into sections, a signal control relay for each section, a signal control circuit for each section for supplying energy to the associated signal control relay in one direction or the other according as the signal control relay for the section next in advance is energized or deenergized, an approach relay for each section normally in one condition but operable to a different condition when the section next in rear be comes occupied by a train, means for each section efiective to connect its signal control relay to the corresponding signal control circuit when the associated approach relay is in its different condition, an auxiliary relay for each section normally in one condition but operable to a different condition when the approach relay for the section next in rear is in its diiferent condition, and means for each section efiective to connect its signal control relay with the corresponding control circuit when the associated auxiliary relay is in its different condition.

GEORGE E. PFLASTERER. 

